1. Field of the Invention
The present invention relates to a dry carbon dioxide capturing device, and more specifically to a dry carbon dioxide capturing device which can improve sorption efficiency by supplying sorbent for absorbing carbon dioxide or exhaust gas containing carbon dioxide to a recovery reactor in multistages at various heights.
2. Description of the Related Art
A carbon dioxide capture apparatus in related art generally employs a wet process to recover CO2. That is, the wet process is carried out by passing CO2-containing gas through an amine solution, to allow CO2 to be absorbed into the solution and regenerating the solution in a regeneration column, thus reusing the solution. However, the wet process has a demerit of further creating waste water during operation of the wet process.
In order to overcome disadvantages of the wet process in the art, a dry process for CO2 recovery has been proposed. This method is to recover CO2 by a dry processing system using two reactors, wherein CO2 fed into a recovery reactor is adsorbed to a solid adsorbent (a dry adsorbent) and removed. The solid adsorbent inflows into a regeneration reactor (‘regenerator’) to remove the adsorbed CO2, H2O is adsorbed to the solid adsorbent in a pre-treatment reactor, and then the adsorbent is recycled in a recovery reactor.
However, as shown in FIG. 2, the recovery reactor has a problem that the quantity of sorbent existing in the reactor is continuously decreasing from the lower end portion into which sorbent is put in (see Daizo Kunii & Octave Levenspiel, Fluidization Engineering, Butterworth-Heinemann, 2nd Edition, 1991, page 195).
Especially in the case of using a fluidized bed reactor as the recovery reactor, the partial pressure of exhaust gas is lowered toward the upper side of the recovery reactor (see FIG. 3), so the sorption ability of sorbent is lowered for exhaust gas (see Esmail R. Monazam & Lawrence J. Shadle and Ranjani Siriwardane, Equilibrium and Absorption Kinetics of Carbon Dioxide by Solid Supported Amine Sorbent, Wiley Online Library, 2010).
Accordingly, the conventional method has a problem that the sorption rate of CO2 by the recovery reactor cannot increase any more.